ascend + basic auto landing + misc

library/lib_vessel_utils.ks

@@ -1,4 +1,4 @@
-run "library/lib_math".
+import("library/lib_math").
 
 declare function WaitForEngineStart{
 	wait until AnyEngineActive().
@@ -41,6 +41,24 @@ declare function GetIsp{
 	return sum / weights.
 }
 
+declare function GetIspForStage{
+	parameter engineState.
+	parameter pressure is 0.
+	LIST ENGINES IN allEngines.
+	local totalThrust is GetThrustOfStage(engineState).
+	local sum is 0.
+	local weights is 0.
+	for eng in allEngines{
+		if eng:stage = engineState {
+			local w is eng:POSSIBLETHRUST / totalThrust.
+			local ispW is eng:ispat(pressure) * w.
+			set sum to sum + ispW.
+			set weights to weights + w.
+		}
+	}
+	return sum / weights.
+}
+
 declare function GetMaxMassFlow{
 	LIST ENGINES IN allEngines.
 	local sum is 0.
@@ -129,4 +147,86 @@ declare function CalculateTimeToImpact{
 	local hRel is curAltitude - tgtAltitude.
 	local disc is ((vs^2) + (2 * g * hRel)).
 	return (vs + sqrt(disc)) / g.
+}
+
+function CalculateMultiStageBurnDuration{
+	parameter dv.
+	if ship:deltav:current >= dv {
+		print "one stage" at (0, 5).
+		return GetBurnTime(dv, ship:maxthrust, ship:mass).
+	}else{
+		print "multi stage" at (0, 5).
+		local burnTime is 0.
+		local remDv is dv.
+		from {local s is ship:stagenum. } until s = 0 step { set s to s-1.} do {
+			if remDv <= 0 {
+				return burnTime.
+			}
+			local cdv is ship:stagedeltav(s):current.
+			local cmass is GetMassOfStage(s).
+			local cthrust is GetThrustOfStage(s).
+			local cisp is GetIspForStage(s).
+			if cdv >= remDv {
+				set burnTime to burnTime + GetBurnTime(remDv, cmass, cthrust, cisp).
+			}else{
+				set burnTime to burnTime + GetBurnTime(cdv, cmass, cthrust, cisp).
+			}
+			set remDv to remDv - cdv.
+		}
+		return burnTime.
+	}
+}
+
+// Burn time from rocket equation
+function GetBurnTime {
+    parameter deltaV.
+	parameter stagethrust is 0.
+	parameter stagemass is 0.
+    parameter isp is 0.
+    
+    if deltaV:typename() = "Vector" {
+        set deltaV to deltaV:mag.
+    }
+    if isp = 0 {
+        set isp to GetIsp().
+    }
+	if stagethrust = 0 {
+		set stagethrust to ship:thrust.
+	}
+	if stagemass = 0 {
+		set stagemass to ship:mass.
+	}
+    
+    local burnTime is -1.
+    if stagethrust <> 0 {
+        set burnTime to stagemass * (1 - CONSTANT:E ^ (-deltaV / isp)) / (stagethrust / isp).
+    }
+    return burnTime.
+}
+
+function GetThrustOfStage {
+	parameter st.
+
+	local totalThrust is 0.
+	LIST ENGINES IN allEngines.
+	for eng in allEngines{
+		if eng:stage = st {
+			set totalThrust to totalThrust + eng:POSSIBLETHRUST.
+		}
+	}
+	return totalThrust.
+}
+
+function GetMassOfStage {
+	parameter st.
+	
+
+	local total is 0.
+	LIST PARTS IN allP.
+	for p in allP {
+		if p:stage <= st {
+			set total to total + p:mass.
+		}
+	}
+	return total.
 }